Projects in our laboratory are concerned with the development and application of techniques for physiologic data acquisition using standard medical fluoroscopy as the source of data input. To accomplish this we have developed a series of devices in conjunction with the biomedical engineering division of the Department of AMES, UCSD School of Medicine which allow accurate quantitation of the changing x-ray flux passing through various organ systems. Three broad areas of investigation are 1) pulmonary ventilation and perfusion without the use of x-ray contrast material; 2) vascular flow rate as measured by the passage of angiographic contrast material; and, 3) tissue perfusion at the arteriolar level as measured by the passage of contrast material. Additionally, cardiac wall motion and myocardial contractility have recently come under investigation in our laboratory as well. Using a combination of the data input sources and mathematical analyses developed in our laboratories, the effects of various angiographic contrast materials on renal vascular physiology is currently under evaluation. Our recently acquired capability for high- speed data reduction allows on-line complex mathematical evaluations based on a type of linear systems analyses.